灰铸铁刀闸阀铸件变形问题的解决

Solving of Deformation of Grey Iron Knife Gate Valve Body Casting

刀闸阀铸件结构复杂,壁厚分布不均匀,理论上容易产生热应力变形缺陷;铸件内腔毛坯尺寸公差为CT7,普通手工树脂砂造型工艺很难满足此公差要求。在采用平作立浇工艺、激冷覆膜砂制芯、控制铁液浇注温度和化学成分等措施的基础上,研究了铸件收缩量和浇注温度、铸件壁厚的关系。铸件收缩量与浇注温度成反比,与铸件壁厚成正比例关系。根据研究结果采取针对性改进措施,有效地解决了铸件变形问题,保证铸件内腔尺寸公差满足图纸设计要求。

Knife gate valve body casting has complicated structure and big difference in wall thickness.Thermal deformation defect is easy to occur in theory.Casting inside cavity tolerance is CT7,which is difficult to achieve by normal resin bonded sand hand molding method.Based on horizontal molding and vertical pouring technology,chilling resin coated sand core making,pouring temperature and chemical composition controlling,etc,relationships between casting contraction and pouring temperature casting wall thickness were studied.Castings contraction is in inverse proportion to pouring temperature while direct proportion to wall thickness.The deformation defect was effectively solved according to above conclusion.Casting inside cavity tolerance can meet designing requirements.